This section is intended to provide a background or context to the invention recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
Conventional fiber placement systems are typically optimized to produce very large and often highly contoured parts that receive little or no post forming prior to curing. The resulting conventional design configurations may present significant disadvantages when used to produce small, substantially flat part blanks, as explained below:
Minimum Course Length (MCL):
Conventional fiber placement systems apply each course of material to the work surface in a more or less continuous fashion, by feeding the tows from the material spools through a complex fiber delivery path, into the nip point of a roller riding along the work surface. This requires that the mechanisms for cutting each tow to the required length be located on the dispensing head, as close to the nip roller as possible. The distance between the cutting mechanism and the nip point at the roller determines the length of the shortest tow (or course) that can be produced and laid. A longer minimum course length dimension thus increases the amount of scrap to be removed during the trimming operation. The minimum course length attainable with the conventional fiber placement configuration may therefore be too long to be practical for producing very small, flat parts.
Complex Tension Control:
Because conventional systems apply each course of material to the work surface in a more or less continuous fashion, each tow must necessarily travel a significant distance from the material spool to the dispensing head, while undergoing the stresses imposed by the repeated bending and twisting required along the path. Because the speed of the tow through the fiber delivery system must match the laydown rate of the material on the work surface, the operations for feeding and cutting each tow to length are typically executed on the fly. These conditions mandate the use of a sophisticated and expensive system for controlling the tension in each individual tow. The costs associated with such a tension control system make a conventional fiber placement system impractical as an alternative to hand layup for producing very small, substantially flat parts.
Contoured Layup Capability:
The configuration of conventional fiber placement systems is driven in part by the need to be able to apply a course of material to work surfaces having fairly complex contours. The requirement for such a capability influences the design in a number of significant ways, the net effect of which drives a system design that is too complex and expensive to be a viable alternative to the hand layup process for small, substantially flat parts, for example:                Conventional systems typically require a dispensing head design that permits each individual tow to be able to be paid out individually while at full layup speed, so as to be better able to conform to the contours of the work surface;        Conventional systems typically require a complex nip roller design with sufficient compliance to accommodate abrupt, localized changes in contour;        Conventional systems typically require a high-powered source of process heat to tackify the part surface on the fly at full layup speed; and        Conventional systems typically require a relatively large manipulator with 6 (and in some cases, 7) degrees of freedom in order to be able to apply a course of material onto the work surface at the correct orientation and path, with sufficient mold clearance.        
A need exists for improved technology, including technology for efficiently producing advanced composite part blanks, especially small, substantially flat advanced composite part blanks.